Switch



July 6, 1943.- J, R FREl 2,323,389

SWITCH Filed oct. 7, 1940 n Y .agr TWIN, 4o /riu INVENTOR Wacom ATTORN EY line 5 5 of Fig. 4; and,

. (Patented July 6, 1943 Jakob R. Frei, Sidney, N. Y., assignmto Bendix Aviation Corporation, South Bend, Ind.,a corporation oi' Delaware Application October '1, 1940, Serial No. 360,101

v(Cl. 200-16) 14 claims.

This invention relates to electrical apparatus, and more particularly to switches of the multiple terminal type.

An object of the present invention is to provide a novel electrical switch of thetype adaptedto make and/or break a plurality of-independent circuits in a predetermined manner.

A further object is to provide a switch of rthe above type with a novel movable contact member mounted so as to accomplish the several circuit changes with a minimum displacement, producing effective and certain operation with a durable and simple construction.

Still another object is to provide means whereby a plurality of circuits may be simultaneously grounded, the connection to ground being assured by novel contact means. l

A stil1 further object'is to provide a novel master switch for rendering inoperative the magnetos of a multi-motored plane and other auxiliary electrical apparatus of said plane and motors.

Still another object is to provide a switch having movable contact members with novel means s for insuring a good electrical connection between the movable and stationary contacts.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when -the same fpended claims. i

, In the drawing, whereinlike reference characters refer to like parts throughout the several views,

Fig. 1 is afront view in elevation, with parts broken away, of one form of switch embodying the present invention;

Fig. 2 1s a sectional'view taken substantially along line 2-2 of Fig. l; y

Fig. 3 is a rear view in elevation of the switch of Figs. l and 2;

Fig. 4 is a detail sectional view of the movable contact member of said switch;

Fig. 5 is a section taken .substantially along Fig. 6 is an enlarged sectional view with parts broken away taken substantially along line 6-6 oi Fis. 4.

The present invention embodies in a compact device means for controlling in a novel manner a plurality of independent electrical circuits in a predetermined manner. This is accomplished with a minimum displacement of a novel movable contact member,` thereby. insuring eillcient, quick and certain operation. In the illustrated embodiment, the novel switch means is oi a type adapted for breaking a plurality of auxiliary and main motor circuits while simultaneously connecting a plurality of other' circuits to a common terminal, such as ground. The rdevice in this form is particularly useful as a master control switch in a multi-motored aircraft in order to break the various light, `auxiliary engine and motor circuits while simultaneously connecting terminals ci the motory magnetos to ground.

`As shown, the novel switch comprises a cylindrical casing I0 of insulating material adapted to carry the stationary contacts, a reciprocable drum ll constituting the movable contact memis read in connection with the accompanying ber and a handle assemblyl2 operatively connected to said drum and adapted to actuate the latter, said assembly being pivotally mounted on a cover piece Il which is rigidly secured to casing l0, preferably by a plurality of counter-sunk screws I3a. A plurality of terminals I4, substantially equally spaced in an annular row about Athe periphery of casing I0, are rigidly xed to the latter, said terminals being nine in number when, for example, the switch is adapted for use as a master control on a four-motored aircraft having two magnetos for each motor.

Each of said terminals comprises a nut I5, a i

screw I0, and a stud l1 (Fig. 2) that is preferably integral with said screw and is embedded in casing I0 with a contact surface il exposed on and substantially ush with the internal periphery of the casing. A second row of terminals l0 similar to terminals Il is provided betweenthe latter and the rear of the casing Il, terminals` I8 having contact surfaces 20 on the interior of said casing.

The desired connections to terminals i4 and l0 are effected by reciprocal movement of drum ii, which is loosely mounted on a stud shaft or rod 2l that is threaded at one end into cover piece Il and retained at the other end in an opening 22 provided therefor in the rear end of casing lli. To actuate drum ll,`a sleeve 23 rigidly secured thereto is provided with a peripheral groove or slot 24 that is engaged by a bifurcated arm 2l.y The latter constitutes one arm of a bell crank lever 28, the other Larm 21 of which extends through an opening 2B in cover I3 to provide a readily accessible handle, "the, pivotal movement of which controls the axial positional drum il on rod 2l. Lever 20 is pivotally mounted' on a pin 29 fixed on opposite sides of opening 28 by means of a pair of brackets 30 (Fig. l). To restrict drum II to reciprocal movement only and to insure proper assembly of the parts, a pin 3I is rigidly attached to said drum and an axially extending slot 32 is provided in casing I3 to be engaged by said pin.

Drum I I is divided axially into two contact carryimsegments 33 and 34 (Fig. 4), and segment 33 wlnohmis preferably integral with sleeve 23 is formed from a suitable conducting material, such as brass. A plurality of circumferentially spaced ball contacts 35 are mounted in the rim of segment 33 (Figs. 2, I4 and 6) and project radially therefrom, said contacts-being resiliently urged outward. To accomplish this, radial recesses 33 are drilled or otherwise provided in the rim of said segment, said recesses being of a suitable size to receive balls 35 and deep enough to permit a spring 31 to be positioned between each of said balls and the bottom of a recess. To retain balls 35 in position, the upper edge of each recess 33 is preferably peened over, such as by a punching operation, to thereby form a lip 33 (Fig. 6) and hence constrict the mouth of the recess so as to prevent the escape of ball 35. Ball contacts 35 correspond in number to the number of terminals I4 .and are circumferentially disposed about segment 33 in corresponding locations to contact surfaces I3 so that every one of the latter surfaces is engaged by one of said contacts when drum Il is axially disposed so that the row of ball contacts 35 is co-planar with the row of said contact surfaces. The spring associated with the ball contacts serves to provide a good electrical connection between the latter and segment 33 and between said balls and contact surfaces I3 when the latter are engaged thereby.

Contact carrying segment 34 is formed from insulating material and comprises a rigid rim 34a and a core 34h (Figs. 4 and 5) of suitable resilient material, such as rubberized fabric. A plurality of pin contacts 39 are slidably mounted in radial openings 33a provided in rim 34a, and core 34h 'bears against said pins and tends to yieldably press the latter radially outward. Pairs of adjacent contacts 39 are electrically connected to each other `by means of conducting strips 43 which are interposed between rim 34a and core 34h, each of said connected pairs of contacts 33 being insulated from the other contacts. It is preferable, in order to prevent shifting of strips 43 and for facilitating assembly, to have each of said strips rigidly attached, as at 43a, to at least, one of the two contacts which are electrically connected thereby, and to bend said strip slightly to cause it to conform more closely to the shape of the interior of rim 34a. Block 34h is preferably provided with a centrally disposed peripheral groove and the periphery within the groove is octagonal to accommodate the bent strips 40. Contacts 33 are so positioned in relation to drum I I that each engages a predetermined one of contact surfaces 23 when said drum is moved to cause the row of terminals I3 to be co-planar with the row ci said contacts, said terminals being thus connected to each other in rs. l:msegrrlents 33 and 34 are secured to each other, preferably by a plurality of rivet-like members 4I (Figs. 2 and 4) which extend axially through said segments and through a plate 4I which may be provided at the rear of seg'ment 34 for the Purpose of fi core 34a in relation to rim 34h. The elements d together by members 4I are preferably bored to receive said members and the openings 4Ia (Fig. 5) thus provided are unequally spaced circumferentially in order to obviate the possibility of an improper assembly of the parts. A pair of peripheral grooves 43 and 4l are preferably provided on the interior of casing IU to be engaged by balls 35 and pins 33, respectively, and to thereby predetermine two positions for drum I I. Groove 44 is suitably located so that when pins 39 engage said groove, al shown in Fig. 2, each of contacts surfaces Il and. therefore, terminals I4 becomes electrically connected to one of said ball contacts and to segment 33. The distance between contacts 35 and contacts 39 in relation to the distance between the rows of terminals I4 and I9 is such that when groove 44 determines the position of drum II, contacts 39 are disconnected from contact surfaces ZI) of terminals I9. On the other hand. when groove 43 determines the position of said drum, i. e., when balls 35 engage the latter groove, said balls are disconnected from terminals Il while pin contacts 39 become connected to termi. nals I9.

When the above switch mechanism operates al the master switch in a four-motored airplane, eight of terminals I4 are connected by suitable leads (not shown) to the ground terminals of the eight magnetos `of the main engines and the ninth terminal is grounded. Accordingly, when said terminals become electrically connected to segment 33 by means of contacts 35, each of the magnetos is grounded by a plurality of circuits. one of the latter consisting of the grounded terminal I4 while others include arm 25 and shaft 2|. Various auxiliary motor and light circuits. for example, are simultaneously controlled by the switch by being connected in series with the paire of normally connected terminals I9. When the switch is in oi position, the magnetos are grounded, as above described, and each of the auxiliary circuits is broken since the pairs of terminals I9 are disconnected by the displacement of pin contacts 39. When the switch is snapped into on position, the ground connection il broken by disengagement of balls 35 and contact surfaces I3 to thereby render the main engine magnetos operative and the auxiliary circuits are rendered operative by the connection of pin contacts 39 with terminals I3.

I! it is desired to radio-shield the above-doscribed mechanism, it is only necessary to attach to the rear of cover I3 a cup-shaped metallic casing having a suitable outlet for the cables attached to terminals I4 and I3.

There is thus provided a novel master switch adapted to control a plurality of circuits in e predetermined manner, the same being effective. for example, to connect a plurality of independ- 'ent terminals to a single common terminal while simultaneously breaking a plurality of power circuits. The switch comprises novel contact means capable of achieving desired circuit changes with a minimum displacement and having means incorporated therewith for insuring a good electrical connection between the movable and stationary contacts. Additionally, the novel switch mechanism comprehended renders it possible to render the entire electrical and ignition systems of an aircraft inoperative with a short movement of a single control lever. The structure of the switch is compact and durable and permits of ready assembly.

Although only a single embodiment of the present invention has been illustrated and Ilescribed, it is to be expressly understood that the same isnot limited thereto. lFor example, it will now be apparent to those skilled in the art that the novel switch means can be adapted for simultaneously breaking andA making all the circuits connected therethrough by spacing the rows of movable contacts akdistance equal to the spacing of the stationary contacts. Various other changes may be made in the design and arrangement of parts without departing from the spirit and scope ofthe invention. For a definition of the invention, reference will be primarily had to the appended claims.

What is claimed is: y

1. In a master switch mechanism, two rows of stationary terminals, mounting means therefor, movable mechanism comprising an insulated section and a conducting section, two sets of contact members, one of said sets being mounted in eacho said sections, yielding means for urging said contact members in the direction of said terminals, means carried by said insulating section adapted to electrically connect the contact members carried thereby in pairs, and actuating means for operating said movable mechanism to y stationary terminals, mounting means therefor,

movable mechanism comprising an insulated section and a conducting section, two sets of contact members, one of said sets being mounted in each of said sections, yielding means for urging said contact members in the direction of said terminals,means carried by said insulating section adapted to connect the contact members carried thereby in pairs, actuating means for operating saidvk movable mechanism to cause the terminals of one of ysaid rows to become electrically connected to the contact members of one of said sets, and means for grounding said conducting section.

3. In a master switch, two rows of ystationary terminals, insulated hollow supporting means for said terminals, mechanism mounted for reciprocal movement in said supporting means, said mechanism comprising an insulated segment and 8 Conducting Segment, two sets of contact members mounted in the rim of said mechanism and projecting radially therefrom, one oi! said sets being carried by said insulating segment and the other set by said conducting segment, conducting means resiliently urging the contact members in said conducting segment radially outward, an insulator yieldingly urgingthe contact members in said insulated segment radially outward, means adapted to connect the contact members carried by said insulated segment in pairs, and actuating means for operating said movable mechanism to cause the terminals of one o! said rows to become electrically connected to the contact members of one of said sets.

members lin said insulated segment radially outward, means adapted to connect the contact members carried by said insulated segment in pairs, andactuating means for operating said movable mechanism tocause the terminals of one of said rows to become electrically connected `conducting means to ground, means electrically connecting pairs of the contactsmounted in said 4. In a master switch, two rows of .stationary insulator, apparatus for moving said conducting and insulating means in unison, and means for predetermining two positions to which said apparatus is adapted to move said insulating and conductingmeans,y the terminals of one row being connected to the contact members of theinsulating means in the first Vof said positions and the terminals of the other row being connected to the contact members of the conducting means in the second of said positions.

6. In a master switch, a casing of insulating material, a plurality of terminals secured in said casing and extending therethrough to provide contact surfaces on the interior of said casing,

said terminals being located in two axially spaced rows, a. drummounted in said casing and adapted for reciprocable movement relative thereto, said drum comprising an insulated section and a conducting section, a set of contacts mounted in said conducting section and adaptedy to engage a row of said contact surfaces `to connect a row of said r. terminals to said conducting section, means for grounding said conducting section, a set of contacts carried by said insulated section, said last-named contacts being connected in pairs and adapted to engage the other row of contact surfaces to complete circuits between pairs of terminals of said row, and means for actuating said drum to cause one of said sets of contacts to be electrically connected to its corresponding row of terminals.

7. Apparatus of the class described comprising a housing including a cup-like member of insulating material and a cover removably secured to said member, a supporting rod extending coaxially of said housing between said cover and the'end wall of said member, a plurality of contact terminals in the wall of said member, means carrying a. plurality of contact elements slid'ably mounted on said rod, and means for reciprocating said contact carrying means to move said elements into and out of electrical engagement with said terminals, said last-named means including a bell crank lever pivotally mounted on said cover and having sliding engagement with the walls of a groove in said contact carrying means.

8. Apparatus of the class described comprising a cylinder-like housing, a supporting rod extending coaxially of said housing between the ends thereof, means carrying contact elements slidably mounted on said rod, means for preventing angular movement of said contact carrying means relative to said housing, a plurality of terminals circumierentially spaced around the wall of said housing, and means pivotally mounted on an end wall of said housing for reciprocat- `ward, an insulator yieldingly urging thecontact ing said contact carrying means on said rod to move said contact elements into and out of electrical engagement with said terminals, the pivotal axis of said pivotally mounted means 'being at right angles to and spaced from said rod and said pivotally mounted means having a. portion slidably engaging the walls of a groove in said mst-named means.

9. In a switch mechanism, a hollow casing, a plurality of contact terminals mounted in the wall o! said casing, and contact carrying means in said casing comprising a supporting member, a ring of insu-ting material, a plate extending across an open side of said ring, a resilient core member in said ring interposed between said supporting member and said plate, means securing said plate, ring and supporting member in assembled relation, a plurality of contact members slidably extending through radial openings in said ring and held by said core member in yielding engagement with the wall of said casing for electrical engagement with said terminals and means electrically connecting the inner ends of adjacent ones of said contact members.

l0. In a switch mechanism, a hollow casing, i

a plurality of terminals mounted in the wall ot said casing, contact carrying means slidably said terminals, and means for reciprocating said contact carrying means -to move said contacts into and out of electrical engagement with said terminals, said last-named means comprising a bell crank lever pivotally mounted on said casing, the pivotal axis for said lever being perpendicular to the direction of movement o'f said contact carrying means and said lever having sliding engagement with the walls of a groove in said contact carrying means.

11. In a switch mechanism, av hollow casing, a plurality of terminals mounted in the wall of said casing, contact carrying means in said casing comprising a ring of insulating material, a resilient core member in said ring, a plurality of contact members slidably extending through radial openings in said ring and held by said core member in yielding engagement with the wall of said casing for electrical engagement with said terminals and means electrically connecting the inner ends of adjacent ones of said contact members, means slidably supporting said contact carrying means in said casing, and means comprising a lever pivotally mounted on said casing for moving said contact carrying means to move said contact members into and out of engagement with said terminals.

12. In a switch mechanism, a cylinder-like set against the wall 'of said ci casing, a plurality oi.' disposed terminals in the` wall of sa ng'. movable contact means in said casing comprising an insulating ring, a plurality of contact elements slidably extending through radial openings in said ring, common means for resiliently pressing said contact elements against the inner wall of said casing and means electricaliyconnecting the inner ends of selected pairs of said contact elements including a resilient metallic strap mechanically connected to one element of each pair and engaging the peripheral surface of said common means, and means for moving said contact carrying means axially of said casing to move said contact elements into and out .of-engagement with said terminals.

13. In a switch mechanism,'a casing, contact carrying means slidably mounted in said casing, a first set of circumferentially spaced and electrically connected contacts on said means, means for yieldingly holding said contacts against the wall of said casing, a first set of terminals mounted' inthe wall of said casing for ,electrical engagement by said contacts,` a second set of cirr cumferentially spaced contacts on said contact carrying means,` .means electrically connecting the contacts of said second set in pairs, means for yieldably holding the cor :ts of said second ing, a second set of terminals mounted in the Wall of said casing Ior electrical engagement by said second set of contacts, and means for moving said contact carrying means axially of said casing, said contacts and terminals being so positioned that said first sets are in electrical engagement when said second sets are out of electrical engagement and said second sets are in electrical engagement when said rst sets are out oi electrical engagement.

14. In a switch mechanism, a hollow casing, means including a'member of electrical insulating'material mounted in the casing for reciprocation therein, a plurality of electrical conductora slidably extending through radial openings in said member at the periphery thereof, resilient insulating means for yieldably pressing said conductors against the inner wall of said casing, and means for electrically connecting the inner ends of certain of said conductors, said last-named means including a plurality of bendable metallic straps engaging the peripheral surface of said resilient insulatingI means, each of said straps being mechanically and electrically connected to at least one of said :onductms and electrically connected to at least ohrA other of said conductors. 

